NASHUA – The Broad Street Parkway is one of the most complicated projects ever undertaken by the city, so it makes sense that it’s now the subject of one of the most complicated maps the city has ever put online.

“I’m not a programmer, so getting in and messing with the actual HTML code can be difficult,” said Angelo Marino, the city’s chief assessor and one of its gurus for GIS, or Geographic Information System, software that allows interactive online maps.

“You’re actually seeing two different layers,” Marino said. “Some services allow you to label, some won’t – we had to mix and match.”

The result, placed on the city’s website Monday, gives information on roughly 75 parcels of land that will be impacted by the parkway as it stretches from Broad Street, south over the Nashua River and down to Pine Street near West Hollis Street.

They range from tiny, quarter-acre lots to large swaths of the Millyard, with purchase prices ranging from mid-level seven figures down to less than $100,000.

The idea is to help people keep an eye on the effect the two-lane, limited-access road will have on the city.

“It’s a hard project for people to understand all the moving parts,” Mayor Donnalee Lozeau said. “We’ve had people working on this map for a long time.”

The interactive aspect, in which different information pops up depending on where you click, required creating a new database. Plenty more information could be included and will be included soon, said Marino, who did the bulk of the work creating the map.

The next steps are adding links to legal documents specific to the purchase or easement on each parcel. An upgrade on the underlying map, showing individual buildings, is also in the works.

“We made it as user-friendly as we could,” Lozeau said. “It’s going to get more (user-friendly) as we go along.”

This map is just the sort of project that GIS is designed to create. Using a mix of improved computers and databases, plus detailed geographic information from GPS systems, it links information with maps in a variety of ways.

It is a favorite of planners and developers, both in the private sector and in government. The city of Nashua has an entire GIS section on its website, accessing maps that show zoning, transportation routes, sidewalk plowing, walking trails and other things.

The city’s uses GIS software from the company Esri, a California-based company that dominates the GIS industry for land use and development.

The $68.7 million Broad Street Parkway will be paid for partly through a $37.6 million city bond and partly through federal money. It is slated to open to traffic by the end of 2014.

David Brooks can be reached at 594-6531 or dbrooks@nashuatelegraph.com.